Anthropometric measurements such as height, weight, body length and head circumference have been used by medical professionals as parameters to monitor the growth of a baby, child or adolescent. Such parameters vary according to the age of the subject. Through population studies, population percentiles of such parameters have been established. It is common practice for pediatricians to measure those parameters for their patients and plot the results on respective growth charts so that the growth status of a child for each of the parameters can be determined. The apparatuses used to measure such parameters include tape measures, standing stadiometers and weighing scales.
Davignon described in CA 2,133,156A and U.S. Pat. No. 5,763,837 how to improve the recording of weight and height, and estimating weight and height growth percentiles. Through the use of a weight and height measurement system, the measured weight and height of the subject is compared to growth height and weight tables relative to the sex and age category of the subject. The system then calculates the percentile weight and height of the subject from these tables.
It is also known from the medical literature that the weight and height of a child is not, by themselves, as indicative of the subject's growth pattern as certain growth indices. Examples of such growth indices are Body Mass Index (BMI) for children and adolescents, which is represented as body mass (kg) divided by the square of body height (m2), weight-for-length for infants, and weight-for-height for preschoolers. While current weight scales and weight/height measurement devices provide BMI results or the results of other indices (WO 98/13674, US 2002/00049546A1, JP2002-165764, JP2001-091346), they do not, to the inventor's knowledge, determine and display percentile information relating to growth indices based on the subject's age and gender. They also do not characterize that information in terms of whether it is considered to be, for example, below normal, normal, above normal, or far above normal.
There is accordingly a need for a measurement device that determines and displays percentile information relating to growth indices, such as BMI, weight-for-length, and weight-for-height, based on the subject's age and gender. There is also a need for a measurement device that readily provides classification information, such as whether the percentile information is considered to below normal, normal, above normal, or far above normal.